Flowmeter



July 2o, y1943.

W. C. WAGNER Filed NOV. 23, 1940 FLOW METER Patented July 20, 1943 UNITED STATES PATENT OFFICE- FLOWMETER.. Walter C1 Wagner, Ardmore, Pa.

Application` November 23, 1940, Serial No. 366308.-

(Cl. i3-230') 3" Claims.

This invention relates to flow metersl and,` more particularly, to rotating element ilow meters.

The purpose of' this invention isto obtain an accurate measurement of? fluid ow or rate of flow by introducing automatic compensation in rotating element flow meters particularly at low'- er rates of flow and also particularly under conditions where. the flow meter is subjected to changes in position, such` as occur when lmeasuring steam` ow on ships when in motion. Ineluded in` the above are both the use of the selfcontained 'meter through which all of the fluid to be measured flows and a proportional new meter through which a proportional part of the` fluid ows;

Heretofore, when rotor type flow meters have been used for measuring proportional flow, it has been the practice to pass a part of the fluidi to `be measured through the meterand the remain- -produced an unrecoverable pressure drop` or loss of head. In my improved apparatus I. havefound it possible to obtain accurate measurement. of fluid now without such appreciable loss lof head by operating my rotor type flow'meter'from the virtual pressure differential developed be-A tween the mouth or inlet. and the vena. contracta of a. differential producing devicel such.` as an orifice or Venturitube. pressurelis largely recovered down stream where .the fluid again ills the pipe and again flowsv at' the lower velocity existing before reaching the differential pressureproducingl device;

In my self-contained meter, automatic compensation is introduced to care` for the: lightrates-of-flow inaccuracies inherent in available designs and in my proportional ilow meter additional compensation is introduced to `care for the low-rates-ofv flow inaccuracies inherent in. both the meter itself and in the diierential` producing device suchfas an orice'plate in a pipe.`

The use of my rotating type meterfresultsi for the firstr time inl high accuracy' measurements substantially over the entire range.` of flow measurement. sults in greaterl certainty ot maintained metering accuracies particularlyv over the lighter load range, which condition is not obtainable in differential type flow meters through which. the fluid flow does not pass. Whereas., heretofore,

the percentage registrationsof uid flow meters at various rates oizow. have been. citedzinterms of full-load` rating, the percentage'. registration of my meter, because of its greater accuracy may be expressed,` in.. terms of the actual rate of flowY at the time of test.

In thisA case, thev In addition, the use. of my meter re- Ak further object of the invention is to improve the accuracy of` flow meters-` usedto accomplish the objects stated andv also for other like purposes.

Another object of the invention is to accurately meter the rate of flow or quantityof fluid such as steamflowing` through a pipe tosupply the demand require-d by equipment employed on a moving ship, more` especially a sea-going vessel subject to great movement.

Stillanother object'` of the invention ist to correct the` error common to iluidl flow metering orices, nozzles,` or other differential producing apparatus, and'theretore. to flow meters dependent upon them,` which occurs becauseA at lower rates of. ii'ow they inherently fail to produce a differential commensurate with. the1 ratefof flow.

Other `objects of. theV invention will.. appear from the following description.

The present invention', generally stated, consists in a-.full flow or a proportional flowmeter having a rotor driven by the velocity and expansion of the uid and a:` forinof paddle-wheel brake or damper of. which somel of they paddles are pivotally suspended'and have their drag surfaces disposed more or. less edgewise in the di'- rection of motionoflthe` rotor to .permit relatively slight Huid-resistance atlower rates of flow, 'and which, by swinging, shaft. the drag.' surface i-'nto a position more-transverse to the4 direction. of motion of the wheel toincrease the fluid-resistance at higher rates of flowand1 high rotational speed of the meter, whereby the registration is relatively increased atlow ratesl of flow. When the meter is usedito' measure proportional flow, the4 compensation, for low rates ot ow is. in-

creasedto take care of. the additional' low-rateof-flow errors introducedby the oriceplate or otherdiierential producing device.

In the following description. reference willfbe` made to the accompanying drawing forming' part hereof and in which:

Fig,` 1 is a side: view- (with parts removed) `of a flow or fluid meter embodying featuresu of the invention and also showing the application of the meter tothe measurement of steam',

Fig. 2 is a perspective view oifpendent parts carried by therotor of theA meterand; embodying features of thek invention;

Fig. 3v is anedge View partly in section of a modification of` the self-adjusting varies ofmy invention; and. i

Fig. 4 is a plan view of another modification Voithe self-adjusting vanes of` my invention. i

- Referring to the drawing, l` indicates a flow or fluid meter. 2 indicates, for-lexampl'e,` a` steamsupply pipe which maylead from a steam/generating boiler 3 through a superheaterto a source oil` steam consumption such as a steam turbine (not shown because too well-understood to require illustration). 5 designates a differentialproducing device of the type producing a vena contracta, such as an orifice plate, interposed in the steam pipe 2. Within the meter there is the usual rotor 6 and there is provided space as at I for a volume of water or other uid. The meter is shown in a bypass connection 8 and 9 on opposite sides of the orice 5 and it is the flow through the bypass which drives the rotor, for example by means of the rotor wheel I9, in the direction of the arrow shown in Fig. 2. The conduit 8 is connected to the upstream side of the orifice 5 and the conduit 9 at the vena contracta of the orifice. The rotor in turn actuates the register ing mechanism II.

The meter is provided with a paddle-wheel brake or damper I2 having xed paddles or vanes I3 arranged in the pool at 'I atwise in the direction of motion of the paddle-wheel and immovably connected with the rotor 6. The paddlewheel is provided with xed radial arms or spokes I4 shown as connected by a ring I5.

The damping effect of xed vanes, such as these paddles I3, as is well-known, corrects for the tendency to run too fast at relatively high rates of ow and high speeds and results in good accuracy of the meter at such loads and speeds, but the meter tends to register too low at relatively low rates of ilow and slow speeds.

By my invention, accuracy of the meter is obtained at relatively light loads or at low speeds without interfering with accuracy at heavy loads or at high speeds by means of self-adjusting dampers such as the vanes or paddles I6 and II.

These vanes are pivoted and suspended from of a loop or stirrup- 'I'he lower edge or margin" of the vane I6 is provided with a narrow web or lip 20 extending backwardly from the direction of movement for the purpose of giving proper direction to the flow of uid past the vane. The arms by which vane I6 is pivoted to bracket I3 may, Vif desired, limit the pivotal movement of the vane but, as there is no tendency for the vane I6 to rise after its face is at right angles to the direction of rotation of the rotor, such stops are generally unnecessary. Similarly the flow past each of the vanes I3 is -guided by a similar lip 2| Normally, the movable vanes I6 and I1, when the rotor is at rest or is moving relatively slowly, hang down and present their drag surfaces more or less edgewise in the direction of rotation. They therefore exert aA minimum of damping effect on the meter at relatively light rates of 110W or low speeds but, with increasingly higher speeds or heavier loads, they are swung back by the increased pressure of the damping uid, thereby presenting more of their drag surfaces normal to the direction of their motion, thus increasing the damping eifect, with consequent maintenance of uniformmeter accuracy over the load range. For each speed of rotation of the motor 6, therefore, the vanes I6 and I1 take up a lixed position. The drag surfaces of vanes I6 and I'I are so shaped and proportioned in relation to the xed vanes or paddles I3 that uniform accuracy is obtained over the complete range of loads or speeds. In Fig. 3 I have illustrated the vane I5 as act-1 ing against a spring 22 secured to the bracket I8 instead of being positioned in equilibrium between the pressure of the fluid and the force of gravity. This construction permits the use of the meter at quite large departure from level without loss of accuracy.

Although I have illustrated and described a construction showing the damper I2 as having two fixed and two variable vanes, it should be understood that any or all of the vanes can be of the automatically adjustable type, and the number of vanes can be varied from a single adjustable vane to as many vanes as desired, proportioned between fixed and variable vanes in any ratio. It is also to be understood that in place of the stirrup shape, the adjustable vanes may have any shape consistent with the principle of providing less drag effect at low speeds.

When the meter is used as a proportional flow meter, that is, when pari; of the total flow is through an orifice plate or other differential-producing device and a proportional part through the meter, the errors of both the flow meter and of the differential-producing device at low rates of flow can be compensated for by suitably proportioning the xed vanes and/or the automatically adjustable vanes. The meter I is shown connected for proportional Iiow through the supply pipe 2. It is obvious, however, thatwhen connected directly in the pipe line the meter will measure total flow. For example, the meterI measures the total flow in the bypass connection 8 and 9.

Because meters hitherto available do not provide satisfactory accuracy over their lower rang of capacity, it has been the practice to operate two or more such meters of differing ranges for satisfactorily metering the different rates of flow in a single pipe, the meter or meters of lower range being rendered inoperative automatically or manually when the flow of fluid exceeded a predetermined rate, and vice versa. The need for this practice is obviated by the use of my meter because it is uniformly accurate overthe entire operating range of uid flow. I n other words, my meter can replace, without sacrifice of metering accuracy, groups of two or more meters of different sensitivities now in use to obtain accurate metering over wide ranges of fluid now,

wth a consequent simplification and economy of equipment and operating expense.

It will be obvious to those skilled in the art that modifications may be made in details of construction and in matters of mere form without departing from thespirit of the invention.

I claim:

1. In a uid meter, a rotor equipped with a radial member, a generally U-shaped paddle element having its arms pivoted to said member and having a marginal web disposed crosswise of the paddle element. l

2. In a flow meter, a rotor equipped with radial spokes, and vanes of which some are imperforate and are immovably attached to the spokes and of which others are pivotally suspended from the spokes and are perforated and provided with marginally-projecting webs.

3. In a uid meter, a rotor equipped with a radial member, and a generally U-shaped paddle element having its arms pivoted to said radial member so that said element is free to rotate about an axis extending radially from the axis of rotation of said rotor.

WALTER C. WAGNER. 

